Teaching. During the next year teaching experience will consist of working with students in the laboratory, and supervising directed readings. Clinical Research. The muscle complex experiments will be conducted on two clinical groups, Parkinson's disease and congenital spastics, to assess multiple muscle interactions and to establish the necessary data base before preceding with single motor unit studies in these populations. Research. Examination of motor unit activity in the normal population will be continued, including the addition of the condition variables (i.e. rate and direction of movement, modified cutaneous input) described in the original proposal.